In order to maintain a safe environment for users on Twitter, we may suspend accounts that violate the Twitter Rules. Common reasons for suspension may include:

Spam: Most of the accounts we suspend are suspended because they are spammy, or just plain fake, and they introduce security risks for Twitter and all of our users. These types of accounts are against our Twitter Rules. Unfortunately, sometimes a real person’s account gets suspended by mistake, and in those cases we’ll work with the person to make sure the account is unsuspended.

...

Abusive BehaviorWe believe in freedom of expression and in speaking truth to power, but that means little as an underlying philosophy if voices are silenced because people are afraid to speak up. In order to ensure that people feel safe expressing diverse opinions and beliefs, we do not tolerate behavior that crosses the line into abuse, including behavior that harasses, intimidates, or uses fear to silence another user’s voice.

Any accounts and related accounts engaging in the activities specified below may be temporarily locked and/or subject to permanent suspension.

Hateful conduct: You may not promote violence against or directly attack or threaten other people on the basis of race, ethnicity, national origin, sexual orientation, gender, gender identity, religious affiliation, age, disability, or disease. We also do not allow accounts whose primary purpose is inciting harm towards others on the basis of these categories.